Removal of COD and color from landfill leachate by using coagulation-fenton’s process

Abstract

Wastewater containing landfill leachates give adverse impacts to the environment especially for surface water and groundwater pollution when it is not collected properly, treated and safely disposed. Leachates are known to have strong odor, color and high concentration of organic and inorganic compounds. This research focused on treatment of landfill leachate by coagulation-Fenton treatment process which was the combination of coagulation-flocculation with Fenton. It was done to compare the performance of coagulation-flocculation with coagulation-Fenton process for suspended solids (SS), chemical oxygen demand (COD), ammoniacal-nitrogen (NH3-N), and turbidity removal as well as the relative effects of different operational parameters such as pH value, concentration of hydrogen peroxide (H2O2), and coagulant dosage of ferric chloride (FeCl3). The landfill leachate sample collected from Padang Siding landfill, Perlis, Malaysia was treated by using FeCl3 as coagulant for coagulation-flocculation while H2O2 as chemical oxidant for Fenton. The most suitable pH for coagulation-flocculation was 7 while for coagulation-Fenton was 3. The most suitable dosage of coagulant and H₂O₂ concentration were 1000 mg/L and 0.5 M respectively. Among both processes, coagulant-Fenton showed the highest removal efficiency for SS, COD, NH3-N and turbidity by 82, 13, 54 and 86% respectively compared with coagulation-flocculation treatment. Thus, the integration of coagulation-Fenton process had increased the removal efficiency of landfill leachate.